*{
	margin: 0;
	padding: 0;
}
.rocket{
	position: fixed;
	bottom: 0;
	right: 0;
	width: 149px;
	height: 249px;
	background: url(../img/rocket_button_up.png) 0 0 no-repeat;
}

.rocket:hover{
	background-position: -149px 0;
}

.active{
	animation: up 1s infinite steps(4);
}

@keyframes up{
	from{
		background-position: -149px 0;
	}
	to{
		background-position: -745px 0;
		}
	}

.box{
	height: 2000px;
	/* width: 100%; */
	background-image: linear-gradient(#fff,#000);
}